To develop self-confidence, become aware of your self-talk. Encourage yourself and avoid putting yourself down. To influence others, encourage them as well. If you must correct someone else's mistakes, be gentle and empathetic.
To increase self-respect, don't put yourself down, call yourself names or engage in other disrespectful behavior towards yourself. To increase your influence with other people, show them that you respect them.
Don't sell yourself or others short. For the sake of your self-respect, appreciate your good points. For the sake of your influence with others, seek out and show appreciation for their strengths.